Method of forming secondary-battery electrodes



(No Model.)

B. M. HUNTER.

METHOD 0]? FORMING SECONDARY BATTERY ELECTRODES.

No. 397,235. Patented Feb. 5,1889.

[HEUIUHM &

FIG. I.

RUDOLPH M. HUNTER, or PHILADELPHIA, PENNsYLvANIA.

METHOD or FORMING SECONDARY-BATTERY ELECTRODES}.

SPECIFICATION forming part of Letters Patent No. 397,235, dated February 5, 1889. I Application filed January 27, 1888. Serial No. 262,132. (No model.) 7

To aZZ 10710111 it may concern: v

Be it known that I,RUDoLPH M. HUNTER, of the city and county of Philadelphia, and State of Pennsylvania, have invented an I Hiprovement in Secondary'Batt-erns, of which the following is a specification.

My invention has reference to the manufac I ture of secondary-battery elements; and it consists of certain improvements, which. are fully set forth in the following specification and shown in the accompanying drawings, which form part thereof. L

Heretofore it has been customary to make secondary-battery elements by placing previously-hardened cylinders or other forms of active materialsuch as oxide of lcad--in molds andthen cast a lead sup 'iorting an electric conducting-frame around said active material. The trouble experienced is that the lead is sluggish in its movement and will not flow readily into and through the long thin slits which are formed between the cylinders or blocks of hard'active material held in the mold. As there are avery large number of these small slits, the danger of .defect from this cause is very great. One defective cast of lead through a slit ruins the whole plate, and consequently a loss of the labor expended and to be expended in recovering the pieces of active material and the remelting of the lead. My object isito form such plates aroundthe active material with a surety Ofsuccess for every cast, and thus reduce the cost of pro-.

duction proportionally, and at the'same time increase the capacity of the-manufacturing plant. The molds whmrhold the active ma terial should be made hot to'prevent chilling I of the flowing lead, and'thisheat with the employment of pure lead is unsatisfactorilyhigh.

In my improvement I am enabled to cause the flow of the lead at a much lower tempera- ,ture without the least danger of the production of defective plates.

In carrying out my invention .1..-. 1a'ce the active material in the .for'mof long cylinders "an d a consequent reduction in cost.

- of same.

as it rises in-the molds .1atera11y through the-h and when castis chilled-or cooled much more quickly. This saves much time in handling The lead is the main part of the fluid cast, and the amount of bismuth added may be varied to produce the fluidity desired. Itsconductivrty to electricity is less than that of lead,.and its ductility when cold is also less; hence it is not desirable to use more'than is absolutely necessary. The slits between the pieces of ITED STATES- PATENT "OFFICE active material in the. molds are,in the preferred form of plate, (see drawings,) very long and narrow, and are also-very small 111 crosssection, and the lead in flowing-through them comes in contact with walls on all sides of a lowertemperature than the melting-polnt of lead, and hence the tendency to the chilling action and liability'to defective plates being produced; 'It is evident that these channels must be as small as possible consistent with strength and conductivity, and the smaller I canmake them in width the greater the area in agiven sized battery of the surface of active material and the resulting capacity .of the cell. It is therefore my obj eat to reduce these bars of lead to the smallest size, and that too without the danger of producing defective plates. It is evident that while I have particular reference to plates made up of cylindrical pieces. of active material that such pieces maybe varied in form as found most convenient and satisfactory, and hence I do notlimit myself tOYthe dei ails of the plate here'shown. 21-; w

-' In the drawlngs, Figure 1 is a cross-section of a mold with the cylinders of active material held in place and ready for castingi Fig:

2 is a front elevation of the completed elec-' trode. or element, and Fig. 3 is a cross-section .is on the .top end, so that incasting the metal flows to the bottom of the mold through the vertical channels arrangedbetween the rows of cylinders formingithevertical bars new ascends and jruns IOC ontal spaces* 15" in the llltlltl bet ween the cylinders t. aiul form the horizontal bars G of the electrode, The metal also rises, forming the bmnuling-ba-rs ll of the t'ltt'lltltlt. It is -e\'i lent that the (luty ol. these small passage-ways i is very great, :llltl it the metal is not exeeetlingtv tluitl the lead will be liable to omgeal in its passage aml [H'Utllltt tlel'eetive bars (l.

temperature in the mohl :UHl a-etive material pieeesaml east from the bottom up I shall have the least temperature in the molil alnl active material. when the leatl is first pourotl heated before the east, aml would also exist without diluting the lead with bismuth or its eq u ivalon t.

In this application l do not elaim the use of bismuth with ltllll astheeom n'mml l'orthe supportingqilate.

llaring now tleseribetl my inventionprhat l elaim as new,anil (lesil'e to seeure by [letters It is evi lent that il I begin with a given in and when itspressure is greatest (lue to the column of leatl pressing down upon that in the bottom oi" the llltllll, aml as the hot lead rises in the mohl the temperatureol' the lllUltl a-ml aetive material at the upper part will inerease, aml this inerease will be substantially proportional to t he decrease in pressure of the leatl boingeast, owing to the shortening of the eolumn ol' the flowing lead. This will insure the lead flowing uniformly thrt'lugh the mohl throughout theeast. It is evident that this :ulvantagewould be lliltl it the mold was not latent, is-

The method of forming seeon(lary-lmttery elements, consisting in warming thmnolt'l, arranging 1ire\'iousl \'-I'or|netl pieees of active material elose together and holtling them rigllll in said mold, setting the mohl on eml, so that the aetive material pieees are loeatet'l one i above the other, aml finally Pasting the llllltl eonilueting metal arouml saitl aetive'matorial pieees whilo so hehl.

lu testimoirvot' whieh invention l hereunto set my hand.

Witnesses:

RIM-1o. 5. una), Jia, E. M. BREeKINREED. 

